Combination pump and separator



Oct. 5, 1965 E. A. PRIJATEL COMBINATION PUMP AND SEPARATOR Filed Dec. 15. 1961 I72 M97225? 1 Edward QPrg'jazZeZ if It/J 7 a, 0g

United States Patent Illinois Filed Dec. 15, 1961, Ser. No. 159,521 3 Claims. (Cl. 233-3) This invention relates to a combination pump and separator. More specifically, this invention relates to a combined unit for pumping fuel containing both liquid and solid contaminants, and simultaneously separating the contaminants therefrom to provide a clean fuel supply.

To date, various devices have been employed for removing contaminants from fuel. Such prior art devices include, for example, the barrier or screen-type filter and the centrifugal revolving drum type separation unit, both of which exemplary devices have several disadvantages. First of all, these units are incapable of removing contaminants in immiscible liquid form, nor are they adapted to be purged of collected contaminants during continuous operation of said units. Moreover, it is often necessary to dissassemble these devices in their entirety in order to remove the contaminants accumulated therein.

Accordingly, this invention has as a major object to provide a combination pumping and separating unit which is effective in completely removing both solid and liquid contaminants and which may be purged of accumulated contaminants during operation. It is particularly useful for aircraft installations where in-flight dumping of the contaminants is particularly desirable.

Other objects of the invention will become apparent from the following specification and the drawings relating thereto, wherein:

FIGURE 1 is a sectional view of the combined pump and separator taken along line 11 of FIGURE 2;

FIGURE 2 is a sectional view taken on line 2-2 of FIGURE 1; and

FIGURE 3 is a top plan view of the impeller.

The combination pump and separator designated generally by numberal includes a housing 11 providing a generally frusto-conical chamber 12, an impeller 13 having the same general configuration of the chamber and a sump 14 for collecting contaminants separated from the fuel.

The housing 11 comprises a casing 17 having a central fuel inlet opening 18 at one end thereof, and a scrolltype fluid discharge passage 19 surrounding the inlet opening communicating with a discharge port 20. At the oposite end of the housing 11 is a removable end closure 21 which is adapted to be secured to the housing by means of a plurality of bolts 22. The closure 21, which may be regarded as the base portion of the housing and together with the casing forms said housing, is provided with a central opening 23 to accommodate bearings 24, 25 for the impeller shaft 26.

The impeller 13 includes a central hub 3% of a generally conical shape, a shaft 26 connected to said hub and rotatably supported within the bearings 24, 25, and means associated with the shaft, preferably in the form of an internally splined section 31, to connect the shaft with a suitable driving means (not shown). The impeller is shown as threaded onto the shaft and retained by a nut 32. Associated with the hub are a set of spiral or helical vanes 33. This portion of the impeller thus acts as a mixed flow pump which upon rotation draws the fluid into the housing. A central frusto-conical member 34, integral with the vanes and carried thereby in surrounding relation, defines with said hub an inlet passage communicating with the central inlet and which may Patented @et. 5, 1965 "ice be regarded as a first pumping stage to force fluid in a generally axial direction through the unit.

The seals shown at 35, 36 serve to isolate the chamber from the other structure and may be of any well-known construction. Seal 35 prevents fluid from by-passing the separation area by flowing between the frusto-conical member 34 and the casing 17 directly out the discharge scroll. Seal 36 prevents leakage of fuel into the bearings 24, 25. A plurality of radial blades 40, carried by said frusto-conical member 34, extend generally axially and have straight edges 41 generally parallel to and adjacent the chamber wall 12. This provides a fluid passage communicating with the scroll discharge outlet 19.

The radial blades 40 are effective to increase the rotational Velocity of the fluid pumped through the annular space between the frusto-conical member 34 and the hub 30 by the helical vanes 33. As fluid is discharged through the annular space, the blades generate centrifugal force tending to impel the fluid against wall 12 of the chamher. The pumping effect from the axial flow impeller is suflicient to overcome the centrifugal force outwardly, forcing the fluid axially through the chamber into the discharge scroll or volute 19 through the annular space 37. Since the outside diameter of the discharge outlet 37 is approximately equal to or slightly less than the outside diameter of the axial flow impeller, the denser materials can not overcome the centrifugal force imparted thereto and are effectively prevented from being carried along by the fluid stream into the discharge volute. This arrangement provides an efficient means for separating contaminants and assures a clean, contaminantfree effluent. It is preferred that a generally circular shroud member 45 be carried by the outer ends of said blades 40 to provide a rotatable inclined wall adjacent the scroll outlet for reasons which will be apparent in the following description.

The housing 11 is formed with an enlarged peripheral wall portion 49 adjacent the base 21 providing a cavity 50 which is tangentially oriented with respect to the chamber. This cavity 50 forms a contaminant discharge outlet extending from said casing and communicating with the sump 14. The terminal portion of said discharge outlet is provided with a flange 51 adapted to be connected to flange 52 on the sump 14 by a conventional collar 53. Ordinarily the unit is disposed so that the cavity and the sump are below the pump and separator to facilitate separation. The contaminants are thus acted on by the force of gravity in addition to the centrifugal forces resulting from their rotation.

The width of the cavity is approximately half the axial length of the blades 40 and is preferably wide enough to allow the shroud to slightly overlap the shoulder 54.

OPERATION The contaminated fuel from tanks in an aircraft, for example, is pumped or fed by gravity to the central fuel inlet. The path of the fuel is shown in FIGURE 1 by arrows, and various points along the path are designated by the reference letters A, B, C, and D. As can be seen from FIGURE 1, fuel passes through the central fuel inlet to point A and thereafter through the inlet passage between the hub and the conical member. Contaminants in the fuel, which may be in solid and/or immiscible liquid form, begin to separate from the fuel during the passage from point A to point B inside the conical member. As the fuel reaches the point B, it moves radially outwardly and is subjected to even greater centrifugal force as the result of the higher rotational velocity of the blades 40. The greater part of the separation takes place in the general vicinity of point B and the contaminants, being denser than the fuel, are carried tangentially by both centrifugal force and gravity into the cavity 59 and finally into the sump 14. The separated contaminants are prevented from re-entering the chamber by the same forces which originally directed them to the sump. Because of the smooth inclined wall of the chamber 12 and the inclined shroud member 45, particles which are thrust thereagainst move outwardly and downwardly along the wall and shroud and are eventually discharged into the cavity 50. The fuel thus moves in a direction from B to C countercurrent to the contaminants deposited on the shroud and the wall and clean fuel is discharged through the annular space 37 between the shroud and the frustoconical member 34 into the scroll discharge passage 19 where the rotational velocity of the fluid is transferred into pressure head for discharge through discharge port 20 in fluid communication with the scroll discharge passage. The passage of fluid from point B to point C is of relatively low velocity, thus offering little resistance to the contaminants moving in the opposite direction.

Under certain flight conditions, the unit may be subjected to inversion or negative g forces which would tend to force the contaminants, previously deposited in the sump, back into the chamber 12. Accordingly, a check valve 56 has been provided of any well-known construction, between the contaminants discharge port and the sump, which valve is adapted to close if the unit is subjected to such forces. This valve is optional since it is possible to design the unit so that the centrifugal force generated Within the chamber 12 is of suflicient magnitude to overcome any tendency for the contaminants to reenter the chamber.

It is possible to purge the pump by merely opening a dump valve 57 in the bottom of the sump and allowing the fuel head to force the contaminants out through the dump valve. In the case of an aircraft installation, the sump is replaced by a conduit leading outside the air frame. The dump valve is then controlled from some remote place, such as the cockpit, by any well-known operating means, thus permitting in-fiight purging. This eliminates ground servicing as required by other contaminant-removal devices. In the event flight purging is not desirable, it is possible to purge the pump with the aircraft grounded and the engines idle by utilizing the fuel head which may be present, or the head produced by the tank-mounted boost pumps. Only a small head is required to purge the unit, and with proper design of the sump, only a minimum quantity of fuel is needed to completely purge the pump of the collected contaminants.

It may also be desirable to use a heater (not shown) associated with the sump and/ or the housing. Since a large portion of the contaminants may comprise ice, it has been found desirable to melt the ice rather than leave the water in the solid state. It will be noted in FIGURE 2 that a projection 55 is provided within the housing adjacent the cavity 50. This projection assists in breaking up relatively large pieces of ice which are separated from the fuel. The blades 40 also promote the disintegration and comminution of large solid particles.

It is to be expressly understood that this invention, in its broadest interpretation, comprises an arrangement for the separation of denser materials from a fluid stream. While I have disclosed a specific embodiment of the invention, it is not to be so limited to the specific combination pump and separator described.

Also, it will be understood that many changes and modifications will be made without departing from the spirit and scope of the invention and that the invention is designed to be comprehended within the scope of the appended claims which should be given a scope consistent with the prior art.

I claim:

1. A combined pump and separator for contaminated fluid comprising a housing having a generally frustoconical shaped chamber therein, means defining a central fluid inlet in said housing communicating with said chamber, a scroll-type fluid discharge passage generally surrounding said inlet and communicating with said chamber, said chamber having a generally smooth peripheral wall diverging towards an enlarged base portion of said housing, an impeller, means in said base portion for rotatably supporting said impeller within said chamber, said impeller including a conically shaped hub member, the axis of which is generally aligned with said inlet, a frusto-conical member having its converged end in sealing relation with said inlet and spaced from and generally surrounding said conical hub, spiral vanes between said conical hub and said frusto-conical member providing a first stage pump means, and a plurality of blades extending radially outwardly from and carried by said frusto-conical member, said blades having edges adjacent to and generally parallel with said chamber Wall, said blades providing a centrifugal separating means between said frusto-conical member and said chamber wall; means defining a peripheral cavity in said housing, said cavity being tangentially disposed to said chamber and adjacent to the base portion of said housing, a downwardly depending sump communicating with said cavity, whereby fluid is drawn through said inlet into said first stage pump means and discharged through said centrifugal separating means into said scroll-type discharge passage while contaminants are separated from the fluid and discharged tangentially outwardly into said cavity and sump.

2. A combined pump and separator for contaminated fluid comprising a housing having a generally frustoconical shaped chamber therein, means defining a central fluid inlet in said housing communicating with said cham ber, a scroll-type fluid discharge passage generally surrounding said inlet and communicating with said chamber, said chamber having a generally smooth peripheral wall diverging towards an enlarged base portion of said housing, an impeller, means in said base portion for rotatably supporting said impeller within said chamber, said impeller including a conically shaped hub member, the axis of which is generally aligned with said inlet, a frusto-conical member having its converged end in sealing relation with said inlet defining means and means spacing the same from and generally surrounding said conical hub, said spacing means comprising spiral vanes between said conical hub and said frusto-conical member providing a axial flow pump means, a plurality of blades extending radially outwardly from and carried by said frusto-conical member, said blades having edges adjacent to and generally parallel with said chamber wall, said blades providing a centrifugal separating means between said frusto-conical member and said chamber Wall, and a shroud member carried by the edges of said blades adjacent the converged end of said chamber; means defining a peripheral cavity in said housing, said cavity being tangentially disposed to said chamber and adjacent to the base portion of said housing and a downwardly de ending sump communicating with said cavity, whereby fluid is drawn through said inlet into said axial flow pump means and discharged through centrifugal separating means into said scroll-type discharge passage while contaminants are separated from the fluid and discharged tangentially outwardly into said cavity and sump.

3. A combined pump and separator for contaminated fluid comprising a housing having a generally frustoconical shaped chamber therein, means defining a central fluid inlet in said housing communicating with said chamber, a scroll-type fluid discharge passage generally surrounding said inlet and communicating with said chamber, said chamber having a generally smooth pe ripheral wall diverging towards an enlarged base portion of said housing, an impeller, means in said base portion for rotatably supporting said impeller within said chamber, said impeller including a conically shaped hub member, the axis of which is generally aligned with said inlet, a frusto-conical member having its converged end in sealing relation with said inlet and spaced from and 5 generally surrounding said conical hub, spiral vanes between said conical hub and said frusto-conical member providing a axial flow pump means, and a plurality of blades extending radially outwardly from and carried by said frusto-conical member, said blades having edges adjacent to and generally parallel with said chamber wall, said blades providing a centrifugal separating means between said frusto-conical member and said chamber Wall; means defining a peripheral cavity in said housing, said cavity being tangentially disposed to said chamber and adjacent to the base portion of said housing, a downwardly depending sump communicating with said cavity, and a dump valve in the bottom of said sump, whereby fluid is drawn through said inlet into said axial flow pump means and discharged through said centrifugal separating means into said scroll-type discharge passage while contaminants are separated from the fluid and discharged tangentially outwardly said cavity and sump.

References Cited by the Examiner UNITED STATES PATENTS 451,543 5/91 Watters 23319 980,001 12/10 Ponten 2333 1,277,676 9/18 Wright 233-45 1,619,652 3/27 Carter 2332 2,610,788 9/52 Edwards 23333 XR 2,724,549 11/55 Brown 2333 XR 2,868,324 1/59 Anderson 23333 3,072,323 1/63 Stoermer 233-33 M. CARY NELSON, Primary Examiner.

GEORGE D. MITCHELL, Examiners. 

1. A COMBINED PUMP AND SEPARATOR FOR CONTAMINATED FLUID COMPRISING A HOUSING HAVING A GENERALLY FRUSTOCONICAL SHAPED CHAMBER THEREIN, MEANS DEFINING A CENTRAL FLUID INLET IN SAID HOUSING COMMUNICATING WITH SAID CHAMBER, A SCROLL-TYPE FLUID DISCHARGE PASSAGE GENERALLY SURROUNDING SAID INLET AND COMMUNICATING WITH SAID CHAMBER, SAID CHAMBER HAVING A GENERALLY SMOOTH PERIPHERAL WALL DIVERGING TOWARDS AN ELARGED BASE PORTION OF SAID HOUSING, AND IMPELLER, MEANS IN SAID BASE PORTION FOR ROTATABLY SUPPORTING SAID IMPELLER WITHIN SAID CHAMBER, SAID IMPELLER INCLUDING A CONICALLY SHAPED HUB MEMBER, THE AXIS OF WHICH IS GENERALLY ALIGNED WITH SAID INLET, A FRUSTO-CONICAL MEMBER HAVING ITS CONVERGED END IN SEALING RELATION WITH SAID INLET AND SPACED FROM AND GENERALLY SURROUNDING SAID CONICAL HUB, SPIRAL VANES BETWEEN SAID CONICAL HUB AND SAID FRUSTO-CONICAL MEMBER PROVIDING A FIRST STAGE PUMP MEANS, AND A PLURALITY OF BLADES EXTENDING REDIALLY OUTWARDLY FROM AND CARRIED BY SAID FRUSTO-CONICAL MEMBER, SAID BLADES HAVING EDGES ADJACENT TO AND GENERALLY PARALLEL WITH SAI D CHAMBER WALL, SAID BLADES PROVIDING A CENTRIFUGAL SEPARATING MEANS BETWEEN SAID FRUSTO-CONICAL MEMBER AND SAID CHAMBER WALL; MEANS DEFINING A PERIPHERAL CAVITY IN SAID HOUSING, SAID CAVITY. BEING TANGENTIALLY DISPOSED TO SAID CHAMBER AND ADJACENT TO THE BASE PORTION OF SAID HOUSING, A DOWNWARDLY DEPENDING SUMP COMMUNICATING WITH SAID CAVITY, WHEREBY FLUID IS DRAWN THROUGH SAID INLET INTO SAID FIRST STAGE PUMP MEANS AND DISCHARGED THROUGH SAID CENTRIFUGAL SEPARATING MEANS INTO SAID SCROLL-TYPE DISCHARGE PASSAGE WHILE CONTAMINANTS ARE SEPARATED FROM THE FLUID AND DISCHARGED TANGENTIALLY OUTWARDLY INTO SAID CAVITY AND SUMP. 